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O Papel do Laser em Endodontia

Carrilho, Ana Margarida Mateus
Fonte: [sn.n.] Publicador: [sn.n.]
Tipo: Dissertação de Mestrado
Publicado em //2012 POR
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Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina Dentária; Nas últimas duas décadas temos vindo a observar um crescente desenvolvimento da tecnologia Laser nas diversas áreas da saúde, inclusive na Medicina Dentária. Dentro destas aplicações, a associação das novas tecnologias às terapêuticas tradicionais na área da Endodontia tem sido alvo de interesse por parte dos investigadores. Sabemos atualmente que um dos principais objectivos da Endodontia é o de devolver ao sistema de canais radiculares as condições ideais de assepsia, eliminando os microrganismos patogénicos, e restabelecendo a função do dente. Deste modo, o insucesso do tratamento Endodôntico atribui-se hoje em dia à permanência dos microrganismos no SCR, não só devido à possibilidade de ocorrer uma desinfeção deficitária, mas também devido à possível re-contaminação, durante o tratamento ou devido a um selamento coronário insuficiente. Uma das principais utilizações dos Lasers na Endodontia prende-se com a eficácia comprovada dos Lasers como auxiliar na desinfeção dos canais radiculares, sendo que estudos científicos também revelam o seu desempenho noutras aplicações como os recobrimentos pulpares...

Stratum corneum lipids liposomes for the topical delivery of 5-aminolevulinic acid in photodynamic therapy of skin cancer: preparation and in vitro permeation study

Pierre, Bernadete R M; Tedesco, Antônio C; Marchetti, Juliana M; Bentley, M V L
Fonte: Biblioteca Digital da Produção Intelectual da USP Publicador: Biblioteca Digital da Produção Intelectual da USP
Tipo: Artigo de Revista Científica
EN
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Abstract Background Photodynamic therapy (PDT) using 5-aminolevulinic acid (5-ALA) is a skin cancer therapy that still has limitations due to the low penetration of this drug into the skin. We have proposed in this work a delivery system for 5-ALA based on liposomes having lipid composition similar to the mammalian stratum corneum (SCLLs) in order to optimize its skin delivery in Photodynamic Therapy (PDT) of skin cancers. Methods SCLLs were obtained by reverse phase evaporation technique and size distribution of the vesicles was determinated by photon correlation spectroscopy. In vitro permeation profile was characterized using hairless mouse skin mounted in modified Franz diffusion cell. Results Size exclusion chromatography on gel filtration confirmed vesicle formation. SCLLs obtained by presented a degree of encapsulation of 5-ALA around 5.7%. A distribution of vesicle size centering at around 500 nm and 400 nm respectively for SCLLs and SCLLs containing 5-ALA was found. In vitro 5-ALA permeation study showed that SCLLs preparations presented higher skin retention significantly (p < 0.05) on the epidermis without SC + dermis...

Stratum corneum lipids liposomes for the topical delivery of 5-aminolevulinic acid in photodynamic therapy of skin cancer: preparation and in vitro permeation study

Pierre, Bernadete R M; Tedesco, Antônio C; Marchetti, Juliana M; Bentley, M V L
Fonte: Biblioteca Digital da Produção Intelectual da USP Publicador: Biblioteca Digital da Produção Intelectual da USP
Tipo: Artigo de Revista Científica
EN
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47.766187%
Abstract Background Photodynamic therapy (PDT) using 5-aminolevulinic acid (5-ALA) is a skin cancer therapy that still has limitations due to the low penetration of this drug into the skin. We have proposed in this work a delivery system for 5-ALA based on liposomes having lipid composition similar to the mammalian stratum corneum (SCLLs) in order to optimize its skin delivery in Photodynamic Therapy (PDT) of skin cancers. Methods SCLLs were obtained by reverse phase evaporation technique and size distribution of the vesicles was determinated by photon correlation spectroscopy. In vitro permeation profile was characterized using hairless mouse skin mounted in modified Franz diffusion cell. Results Size exclusion chromatography on gel filtration confirmed vesicle formation. SCLLs obtained by presented a degree of encapsulation of 5-ALA around 5.7%. A distribution of vesicle size centering at around 500 nm and 400 nm respectively for SCLLs and SCLLs containing 5-ALA was found. In vitro 5-ALA permeation study showed that SCLLs preparations presented higher skin retention significantly (p < 0.05) on the epidermis without SC + dermis...

Ação de corantes fotossensíveis em meio homogêneo e micro heterogêneo de lipossomos no controle do crescimento de Streptococcus mutans; Action of photosensitizers dyes in homogeneous and liposomal microheterogeneous medium to control Streptococcus mutans growing

Paulino, Tony de Paiva
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 13/11/2006 PT
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Desequilíbrios no desenvolvimento da microbiota bucal podem gerar algumas patologias e, entre elas, está a cárie dental, uma doença crônica - contagiosa, de etiologia multifatorial, mas extremamente relacionada à bactéria Streptococcus mutans, que através de seu metabolismo fermentativo destrói estruturas mineralizadas do dente. Além disso, o aumento da resistência à antibioticoterapia, devido à existência do biofilme (também formado pelo S. mutans) e aos tratamentos bactericidas mal sucedidos, faz do desenvolvimento de técnicas antimicrobianas alternativas um importante foco nesta área de pesquisa. Assim, na busca de novas metodologias contra microrganismos, estudos usando a Terapia fotodinâmica (TFD) têm sido empregados para se obter a inativação de bactérias como o S. mutans. A TFD é uma modalidade terapêutica em que há a integração de uma luz visível, um corante e oxigênio que quando interagem, levam à produção de diferentes espécies reativas de oxigênio (ERO?s) que irão desencadear uma seqüência de eventos biológicos, resultando numa possível morte ou inativação celular, inclusive de microrganismos como o S. mutans. O objetivo deste trabalho foi avaliar a ação da TFD sobre a bactéria S. mutans em meio planctônico ou formando biofilme. Assim...

Influência da terapia fotodinâmica na manutenção da crista óssea alveolar periimplantar; Influence of photodynamic therapy in the maintenance of peri-implant bone crest

Franco, João Eduardo Miranda
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 02/07/2014 PT
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A colonização bacteriana no sulco periimplantar ocorre muito precocemente, logo após a cirurgia de instalação dos implantes. Com este intuito, o projeto foi proposto a fim de avaliar o efeito da terapia fotodinâmica (PDT) na manutenção da crista óssea alveolar. Em um estudo de boca dividida, 20 pacientes foram reabilitados com implantes Standard Plus (Straumann®), divididos em dois grupos: um grupo controle (GC) e um grupo submetido à terapia fotodinâmica (GPDT), cujo protocolo foi: densidade de energia 120J/cm2, potência de 40mW, associada ao corante azul de metileno a 0,005%. As aplicações foram realizadas no dia da instalação do implante, após 15, 30 e 45 dias. As coletas microbiológicas foram efetuadas no período inicial e 6ª semana, nos dois grupos, utilizando cones de papel estéril. No GPDT, outras duas coletas foram realizadas após aplicação da terapia: no dia da cirurgia e após 45 dias. As unidades formadoras de colônias totais (UFCt) e pigmentadas de preto (UFCpig) foram contadas. Dados clínicos (Índice de Placa- IP e Sangramento a Sondagem- SS modificados por Mombelli) foram obtidos na 6a semana, 6 meses e 1 ano. Análise radiográfica, com radiografias periapicais, foram efetuadas utilizando a técnica da subtração radiográfica. As películas foram digitalizadas com o escaner SprintScan 35 Plus - Polaroid. Com softwares de manipulação de imagens (Adobe Photoshop CS2®- Califórnia...

Photodynamic therapy of oral candidiasis hi hiv-positive patients

Cadastro, G.; Giovani, E.; Saginur, R
Fonte: Medimond S R L Publicador: Medimond S R L
Tipo: Conferência ou Objeto de Conferência Formato: 103-107
ENG
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The conventional treatments for Candidiasis include therapies that promote serious side effects to patients. Recent research indicates the use of red emission laser associated with a blue photosensitizer as a current method for microbial reduction. This study aimed to evaluate the effectiveness of Photodynamic Therapy in the treatment of oral candidiasis in HIV patients. The response to treatment by the photodynamic therapy has been demonstrated successfully in 100% of the total sample, as in the 7th and 21st days, confirmed he complete absence of clinical and cytological lesions. This therapy is enhanced by its easy applicability and no adverse side effects making it an alternative method of effective recommended treatment.

Evaluation of resistance development and viability recovery by a non-enveloped virus after repeated cycles of aPDT

Costa, L; Tome, JPC; Neves, MGPMS; Tome, AC; Cavaleiro, JAS; Faustino, MAF; Cunha, A; Gomes, NCM; Almeida, A
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
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Nowadays, the emergence of drug resistant microorganisms is a public health concern. The antimicrobial photodynamic therapy (aPDT) has an efficient action against a wide range of microorganisms and can be viewed as an alternative approach for treating microbial infections. The aim of this study was to determine if a model target virus (T4-like bacteriophage), in the presence of the tricationic porphyrin 5,10,15-tris(1-methylpyridinium-4-yl)-20-(pentafluorophenyl)porphyrin tri-iodide (Tri-Py(+)-Me-PF), can develop resistance to aPDT and recover its viability after photodynamic treatments. To assess the development of aPDT resistance after repeated treatments, a suspension of T4-like bacteriophage was irradiated with white light (40 W m(-2)) for 120 min in the presence of 5.0 mu M of Tri-Py(+)-Me-PF (99.99% of inactivation) and new phage suspensions were produced from the surviving phages, after each cycle of light exposure. The procedure was repeated ten times. To evaluate the recovery of viral viability after photoinactivation, a suspension of T4-like bacteriophage was irradiated with white light for 120 min in the presence of 5.0 mu M of Tri-Py(+)-Me-PF on five consecutive days. In each day, an aliquot of the irradiated suspension was plated and the number of lysis plaques was counted after 24...

Toxoplasmosis retinochoroiditis after photodynamic therapy and intravitreal triamcinolone for a supposed choroidal neovascularization: a case report

Nóbrega,Mário Junqueira; Rosa,Evandro Luís
Fonte: Conselho Brasileiro de Oftalmologia Publicador: Conselho Brasileiro de Oftalmologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2007 EN
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The purpose is to report a complication after photodynamic therapy (PDT) and intravitreal triamcinolone for a presumed choroidal neovascularization in age-related macular degeneration. Photodynamic therapy and intravitreal triamcinolone were used in an 84-year-old man with choroidal neovascularization in the left eye. Forty-five days after therapy, the patient returned with a severe necrotizing uveitis in the posterior pole and vitritis. Laboratory investigation disclosed a high anti-Toxoplasma IgG titer. Therapy with pyrimethamine, sulfadiazine and folinic acid resulted in total lesion healing although central vision was lost. Intravitreal triamcinolone may have had an influence on the exacerbation of retinochoroiditis in the posterior pole of the patient. Although rare, this complication may not be disregarded in the cases that require intraocular corticosteroids for treatment of several conditions, especially in patients who had previously suffered from toxoplasmosis infection.

Photodynamic therapy of normal rat arteries after photosensitisation using disulphonated aluminium phthalocyanine and 5-aminolaevulinic acid.

Grant, W. E.; Speight, P. M.; MacRobert, A. J.; Hopper, C.; Bown, S. G.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1994 EN
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Photodynamic therapy of cancer exposes adjacent arteries to the risk of injury and the possibility of haemorrhage and thrombosis. The nature of photodynamic injury to normal arteries has not been satisfactorily defined, and the ability of arteries to recover with time is unclear. To clarify these issues, we have investigated the effects of PDT on rat femoral arteries, using a second-generation photosensitiser, disulphonated aluminium phthalocyanine, and a new method of photosensitisation, using endogenous synthesis of protoporphyrin IX following systemic administration of 5-aminolaevulinic acid (ALA). Pharmacokinetic studies of sensitiser fluorescence were carried out to determine peak levels of sensitiser. Subsequently photodynamic therapy at times corresponding to maximal fluorescence was performed using two light doses, 100 and 250 J cm-2. The nature of injury sustained and recovery over a 6 month period was investigated. Three days following PDT, all vessels treated showed complete loss of endothelium, with death of all medial smooth muscle cells, leaving an acellular flaccid artery wall. No vascular occlusion, haemorrhage or thrombosis was found. A striking feature was the lack of inflammatory response in the vessel wall at any time studied. Re-endothelialisation occurred in all vessels by 2 weeks. The phthalocyanine group showed repopulation of the media with smooth muscle cells to be almost complete by 3 months. However...

Treatment of ovarian cancer with photodynamic therapy and immunoconjugates in a murine ovarian cancer model.

Goff, B. A.; Blake, J.; Bamberg, M. P.; Hasan, T.
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em /10/1996 EN
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In photodynamic therapy (PDT), photosensitisers accumulate somewhat preferentially in malignant tissues; photoactivation with appropriate wavelength of light release toxic molecular species which lead to tumour tissue death. In order to target ovarian cancer with increased specificity, a chlorin-based photosensitiser (chlorin e6 monoethylendiamine monoamide) was conjugated to OC125, a monoclonal antibody recognising an antigen expressed in 80% of non-mucinous ovarian cancers. In previous work, this immunoconjugate (IC) was shown to be selectively phototoxic to cancer cells from ovarian cancer patients ex vivo and to localise preferentially in ovarian cancer tissue in vivo. In this study we report results from in vivo phototoxicology and photodynamic treatment studies using this IC in a murine model for ovarian cancer. A comparison of single vs multiple treatments was also made. For in vivo experimentation, Balb C nude mice were injected with 30 x 10(6) NIH:OVCAR 3 cancer cells to create an ascitic tumour model. Animals were then given intraperitoneal injections of the immunoconjugate (0.5 mg kg-1). Twenty-four hours later the intraperitoneal surfaces were exposed to 656 nm light from an argon-ion pumped-dye laser (50 mW, 656 nm), using a cylindrical diffusing tip fibre. The overall treatment was given either once or multiply. No animals died from treatment complications. Twenty-four hours following one and three PDT treatments...

Modification by vasoactive drugs of tumour destruction by photodynamic therapy with haematoporphyrin derivative.

Cowled, P. A.; Forbes, I. J.
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em /06/1989 EN
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Since the vascular endothelium is a primary site of damage after photodynamic therapy (PDT), it seemed likely that drugs which affect the vasculature may modify the outcome of PDT. Noradrenaline, propranolol, hydralazine and phenoxybenzamine inhibited photodynamic damage to tumours if these drugs were administered concurrently with HPD, 2 h before irradiation. This inhibition was associated with reduced uptake of HPD into tumours. There was no inhibition if irradiation was delayed until 24 h after administration of vasoactive drug, presumably because HPD uptake continued after the drugs had ceased to affect the vasculature. Verapamil enhanced photodynamic destruction of tumours when administered concurrently with HPD and the enhancement was associated with increased uptake of HPD into tumours. Verapamil neither increased uptake of HPD nor enhanced photodynamic destruction of cells in vitro. When verapamil was administered after irradiation, regrowth of tumours was inhibited. A similar effect was previously demonstrated with glucocorticoids. Other calcium channel blocking agents diltiazem and nifedipine had no effect on uptake of HPD or inhibition of regrowth of tumours after PDT. Inhibition of capillary or stromal ingrowth into tumours seems a plausible explanation of this effect of verapamil. This commonly used drug may be useful to enhance the efficacy of PDT.

Adjuvant therapy for pituitary adenomas: the possible role of photodynamic therapy.

Marks, P. V.
Fonte: Royal College of Surgeons of England Publicador: Royal College of Surgeons of England
Tipo: Artigo de Revista Científica
Publicado em /07/1995 EN
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Although benign, pituitary adenomas may not always be curable by surgery alone. This is usually owing to dural infiltration and the technical problems of removal of involved dura in the sellar region. In such circumstances, some form of adjuvant therapy may be needed to address residual tumour and forestall recurrence. Radiotherapy and drugs, such as bromocriptine or octreotide, although effective are far from ideal adjuvant therapies and this has led to the study of the effects of photodynamic therapy on pituitary adenomas. It has been shown that photodynamic therapy using the photosensitising drugs haematoporphyrin derivative and aluminium phthalocyanine is active experimentally against these tumours. This could provide another useful weapon to use against these challenging lesions.

Therapeutic and Aesthetic Uses of Photodynamic Therapy Part five of a five-part series: ALA–PDT and MAL–PDT What Makes Them Different

Gold, Michael H.
Fonte: Matrix Medical Communications Publicador: Matrix Medical Communications
Tipo: Artigo de Revista Científica
Publicado em /02/2009 EN
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The use of photodynamic therapy has increased dramatically over the past several years. More clinicians are utilizing this therapy and additional indications for its use have become available. The photosensitizers that are utilized for this therapy differ and have been used differently over the past 10 years of our experience with photodynamic therapy. This manuscript examines the photosensitizers and the differences between them as well as reviews the literature on photosensitizers.

Effective Combination of Photodynamic Therapy and Imiquimod 5% Cream in the Treatment of Actinic Keratoses: Three Cases

Held, Laura; Eigentler, Thomas Kurt; Leiter, Ulrike; Garbe, Claus; Berneburg, Mark-Jürgen
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
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Background. The therapy for actinic keratoses includes photodynamic therapy (PDT) and imiquimod 5% cream. The sequential use of both could result in better clinical outcomes. Objectives. To enhance efficacy of therapies while improving tolerability, convenience, and patient adherence with a scheme combining two concomitant or sequential AK treatments. Methods. All patients underwent one session of conventional PDT. Two weeks after, the PDT imiquimod 5% cream was applied to the treatment area once daily for three days per week. One course continued for four weeks followed by a clinical evaluation and decision about further treatment. Patients who had not cleared all of their AK lesions in the treatment area in course 1 participated in a second 4-week course of treatment. Limitations. Small size of population. Results. Three participants were enrolled. Two patients showed complete clinical clearance of AKs. The effect was also noted after long-term followup, at months seven and eleven. No subject discontinued for an adverse event. There were severe local skin reactions in two participants which were severe erythema, scaling, and crusting. One patient showed no response to the therapy. Conclusions. Photodynamic therapy followed by imiquimod was well tolerated and improved reduction of actinic keratoses. This initial proof-of-concept should be studied in larger clinical trials.

In Vivo Small Animal Imaging for Early Assessment of Therapeutic Efficacy of Photodynamic Therapy for Prostate Cancer

Fei, Baowei; Wang, Hesheng; Chen, Xiang; Meyers, Joseph; Mulvihill, John; Feyes, Denise; Edgehouse, Nancy; Duerk, Jeffrey L.; Pretlow, Thomas G.; Oleinick, Nancy L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 29/03/2007 EN
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We are developing in vivo small animal imaging techniques that can measure early effects of photodynamic therapy (PDT) for prostate cancer. PDT is an emerging therapeutic modality that continues to show promise in the treatment of cancer. At our institution, a new second-generation photosensitizing drug, the silicon phthalocyanine Pc 4, has been developed and evaluated at the Case Comprehensive Cancer Center. In this study, we are developing magnetic resonance imaging (MRI) techniques that provide therapy monitoring and early assessment of tumor response to PDT. We generated human prostate cancer xenografts in athymic nude mice. For the imaging experiments, we used a high-field 9.4-T small animal MR scanner (Bruker Biospec). High-resolution MR images were acquired from the treated and control tumors pre- and post-PDT and 24 hr after PDT. We utilized multi-slice multi-echo (MSME) MR sequences. During imaging acquisitions, the animals were anesthetized with a continuous supply of 2% isoflurane in oxygen and were continuously monitored for respiration and temperature. After imaging experiments, we manually segmented the tumors on each image slice for quantitative image analyses. We computed three-dimensional T2 maps for the tumor regions from the MSME images. We plotted the histograms of the T2 maps for each tumor pre- and post-PDT and 24 hr after PDT. After the imaging and PDT experiments...

Efficient Photodynamic Therapy on Human Retinoblastoma Cell Lines

Walther, Jan; Schastak, Stanislas; Dukic-Stefanovic, Sladjana; Wiedemann, Peter; Neuhaus, Jochen; Claudepierre, Thomas
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 31/01/2014 EN
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Photodynamic therapy (PDT) has shown to be a promising technique to treat various forms of malignant neoplasia. The photodynamic eradication of the tumor cells is achieved by applying a photosensitizer either locally or systemically and following local activation through irradiation of the tumor mass with light of a specific wavelength after a certain time of incubation. Due to preferential accumulation of the photosensitizer in tumor cells, this procedure allows a selective inactivation of the malignant tumor while sparing the surrounding tissue to the greatest extent. These features and requirements make the PDT an attractive therapeutic option for the treatment of retinoblastoma, especially when surgical enucleation is a curative option. This extreme solution is still in use in case of tumours that are resistant to conventional chemotherapy or handled too late due to poor access to medical care in less advanced country. In this study we initially conducted in-vitro investigations of the new cationic water-soluble photo sensitizer tetrahydroporphyrin-tetratosylat (THPTS) regarding its photodynamic effect on human Rb-1 and Y79 retinoblastoma cells. We were able to show, that neither the incubation with THPTS without following illumination...

Aluminum–phthalocyanine chloride associated to poly(methyl vinyl ether-co-maleic anhydride) nanoparticles as a new third-generation photosensitizer for anticancer photodynamic therapy

Muehlmann, Luis Alexandre; Ma, Beatriz Chiyin; Longo, João Paulo Figueiró; Almeida Santos, Maria de Fátima Menezes; Azevedo, Ricardo Bentes
Fonte: Dove Medical Press Publicador: Dove Medical Press
Tipo: Artigo de Revista Científica
Publicado em 07/03/2014 EN
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Photodynamic therapy is generally considered to be safer than conventional anticancer therapies, and it is effective against different kinds of cancer. However, its clinical application has been significantly limited by the hydrophobicity of photosensitizers. In this work, a system composed of the hydrophobic photosensitizer aluminum–phthalocyanine chloride (AlPc) associated with water dispersible poly(methyl vinyl ether-co-maleic anhydride) nanoparticles is described. AlPc was associated with nanoparticles produced by a method of solvent displacement. This system was analyzed for its physicochemical characteristics, and for its photodynamic activity in vitro in cancerous (murine mammary carcinoma cell lineage 4T1, and human mammary adenocarcinoma cells MCF-7) and noncancerous (murine fibroblast cell lineage NIH/3T3, and human mammary epithelial cell lineage MCF-10A) cell lines. Cell viability and the elicited mechanisms of cell death were evaluated after the application of photodynamic therapy. This system showed improved photophysical and photochemical properties in aqueous media in comparison to the free photosensitizer, and it was effective against cancerous cells in vitro.

Antimicrobial photodynamic therapy: an effective alternative approach to control fungal infections

Baltazar, Ludmila M.; Ray, Anjana; Santos, Daniel A.; Cisalpino, Patrícia S.; Friedman, Adam J.; Nosanchuk, Joshua D.
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 13/03/2015 EN
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Skin mycoses are caused mainly by dermatophytes, which are fungal species that primarily infect areas rich in keratin such as hair, nails, and skin. Significantly, there are increasing rates of antimicrobial resistance among dermatophytes, especially for Trichophyton rubrum, the most frequent etiologic agent worldwide. Hence, investigators have been developing new therapeutic approaches, including photodynamic treatment. Photodynamic therapy (PDT) utilizes a photosensitive substance activated by a light source of a specific wavelength. The photoactivation induces cascades of photochemicals and photobiological events that cause irreversible changes in the exposed cells. Although photodynamic approaches are well established experimentally for the treatment of certain cutaneous infections, there is limited information about its mechanism of action for specific pathogens as well as the risks to healthy tissues. In this work, we have conducted a comprehensive review of the current knowledge of PDT as it specifically applies to fungal diseases. The data to date suggests that photodynamic treatment approaches hold great promise for combating certain fungal pathogens, particularly dermatophytes.

Influência de dendrímeros e da iontoforese na penetração da protoporfirina IX em tumores cutâneos; Influence of dendrimers and iontophoresis in protoporphyrin IX penetration into skin tumors

Pimenta, Laura Freire Cardoso
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/11/2013 PT
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A terapia fotodinâmica (TFD) associada à administração tópica de agentes fotossensibilizantes é uma terapia promissora para o tratamento tópico do câncer de pele. A protoporfirina IX (PpIX) é uma substância fotodinamicamente ativa usada na TFD, entretanto, devido a sua alta lipofilia ela forma agregados em meio aquoso, o que diminui sua atividade fotodinâmica e dificulta sua administração na pele. Assim, sistemas de liberação nanoparticulados vêm sendo investigados para melhorar a distribuição da PpIX na pele e facilitar sua penetração até as células tumorais. Os dendrímeros de poliamidoamina (PAMAM) representam uma nova geração de nanosistemas que tem despertado grande interesse nos últimos anos. Eles são uma classe especial de polímeros que apresentam estrutura muito ramificada e regular e que interagem com a PpIX formando complexos (nanopartículas dendriméricas de PpIX-PAMAM). A aplicação de uma corrente elétrica de baixa intensidade, conhecida como iontoforese, pode influenciar na penetração cutânea dessas nanopartículas, direcionando-as para o interior das células. Desta forma, o objetivo deste trabalho foi avaliar a influência da iontoforese e de nanopartículas de PAMAM de geração 4 hidroxilado (PAMAM G4-OH) com a PpIX na localização subcelular e penetração deste agente fotossensibilizante em tumores cutâneos. Assim foram preparados complexos de PpIX-PAMAM...

Liquid Crystal Nanodispersions Enable the Cutaneous Delivery of Photosensitizer for Topical PDT: Fluorescence Microscopy Study of Skin Penetration

Garcia Praca, Fabiola Silva; Garcia Medina, Wanessa Silva; Petrilli, Raquel; Lopes Badra Bentley, Maria Vitoria
Fonte: BENTHAM SCIENCE PUBL LTD; SHARJAH Publicador: BENTHAM SCIENCE PUBL LTD; SHARJAH
Tipo: Artigo de Revista Científica
ENG
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Topical photodynamic therapy (PDT) has been applied to almost all types of nonmelanoma skin cancer and numerous superficial benign skin disorders. Strategies to improve the accumulation of photosensitizer in the skin have been studied in recent years. Although the hydrophilic phthalocyanine zinc compound, zinc phthalocyanine tetrasulfonate (ZnPcSO4) has shown high photodynamic efficiency and reduced phototoxic side effects in the treatment of brain tumors and eye conditions, its use in topical skin treatment is currently limited by its poor skin penetration. In this study, nanodispersions of monoolein (MO)-based liquid crystalline phases were studied for their ability to increase ZnPcSO4 uptake by the skin. Lamellar, hexagonal and cubic crystalline phases were prepared and identified by polarizing light microscopy, and the nanodispersions were analyzed by dynamic light scattering. In vitro skin penetration studies were performed using a Franz's cell apparatus, and the skin uptake was evaluated in vivo in hairless mice. Aqueous dispersions of cubic and hexagonal phases showed particles of nanometer size, approximately 224 +/- 10 nm and 188 +/- 10 nm, respectively. In vitro skin retention experiments revealed higher fluorescence from the ZnPcSO4 in deeper skin layers when this photosensitizer was loaded in the hexagonal nanodispersion system when compared to both the cubic phase nanoparticles and the bulk crystalline phases (lamellar...